Carbon dioxide is one of the useful chemicals, because it is nontoxic, nonflammable and abundant in nature. On the other hand, carbon dioxide is notorious for a major cause of air pollution and global warming, which explains that reducing its emittance is becoming nowadays a justifiable action for sustainable development.
Generally, the conversion technology from carbon dioxide as a reactant to produce aliphatic polycarbonate with high value utilizes catalyst containing metal center, ligand, and active anion. In the presence of catalyst, carbon dioxide and epoxide are alternatively bounded to each other and these monomers form a repeating unit, and then this unit grows into a polymer.
A major reaction pathway toward aliphatic polycarbonate is as follow:

Aliphatic polycarbonate has excellent transparency, good barrier properties against water and oxygen, printability, etc. It does not generate smoke when burning, which means it can be applicable to nontoxic materials.
Many research groups have tried to develop this catalytic conversion technology enabling alternating copolymerization of carbon dioxide and epoxide, however, it was not easy to attain e commercial feasibilities due to low selectivity, low polymer yield and excessively long reaction time. In other words, there has not been any continuous process introduced to produce aliphatic polycarbonate in large quantity.
Up to now, polycarbonate that is industrially used is aromatic polycarbonate, coming from bisphenol A and phosgene which are both toxic to human body. Therefore, aliphatic polycarbonate has high environment-friendly values because it does not only use toxic materials but also it reduces or consumes carbon dioxide, in which its emitting level should be reduced.
The present invention relates to a continuous process of aliphatic polycarbonate polymerization in large amount from carbon dioxide with epoxide compound.